It is well known to mount electronic chassis units in racks in which the chassis units are in stacked relationship and are attached to the vertical rails at the four corners of the racks. Because all chassis units are not exactly the same width, it sometimes becomes difficult to mount such chassis units on the vertical rails of a rack. The width variations are sometimes small and sometimes relatively large.
In the case of large width variations, a previous technique for attaching the chassis units to the rails of the rack has required complex brackets, hardware and custom milled spacers or shims for each type or size of chassis units. This technique has proven to be very costly in engineering, manufacturing and installation time. Two or more workmen can spend several hours just to install a single chassis unit in a rack because the dimensional variations of the chassis unit can require a considerable amount of machining time to make spacers or brackets so that the chassis unit can be safely and reliably attached to the rails of the rack. Because of these drawbacks, a need exists for an improved means and technique for securing electronic chassis units of the type described to racks to compensate for width variations in the chassis units while providing for infinite vertical adjustment of the chassis units on the racks. The present invention satisfies this need.